Telephone receiver



April 27 1926.

s G, BROWN TELEPHONE RECEIVER Filed May 5. 1 23 T all whom it mayconcern:

- of a stamping or stamplngs.

Patented Apr. 27 1926.

UNITED. STATES PATENT OFFICE.

TELEPHONE RECEIVER.

Application filed May 3,

Be it known that I, SIDNEY GEORGE BROWN, a subject of the vKing of GreatBritain, re-

siding at Victoria Road, Willesden Lane,

North Acton, in the county of Middlesex, England, have invented certainnew and useful Improvements in or Relating to Telephone Receivers, ofwhich the following is a. specification.

This invention relates to telephone receivers or head phones and has forits chief object to enable such devices tobe made more economically thanheretofore, without impairing their efficiency. Head phone receivers asat present made usually comprise an ebonite or other composition cap,which fits against the ear of the listener, which cap is screwed uponthe edge of a light aluminium or other metal case carrying the diaphragmand a receiving electromagnet the poles of which approach closely to theinner.

ace of the diaphragm.

In such receivers the pole pieces have hitherto been of iron, the magnetconsisting According to one feature of this invention (which isapplicable to various types of telephone receiver) the magnet stampingis stamped out of sheet metal and is itself formed with integral tongueswhich when bent up constitute the pole pieces, the tongues being soshaped and situated in the stamping gas, when bent up, to form adjacentuprighti ole pieces the combined lengths of which are considerablygreater than the distance separating them. For this purpose, in one formof stamping in which the magnet may be of ring or part ring form, thetongues are formed in the stamping so as to extend past or overlap eachother and on bending up to form pole pieces which are staggered or sideby side. Or the stamping may have tongues at one side which are directedtowards each other and can be bent up so as to form pole pieces havingtheir vertical edges adjacent. Or the stamping may be bent up so as toconstitute a ring of pole pieces instead of the pair usually supplied,provided with separate coils or a single ring coil common to the group.In any case the poles can be as closely ad acent to each other as isrequired, while providing for the necessary length of the pole pieces tocarry the rerciver coils.

According to a further feature of this invention the aluminium or otherlight metal 1923. Serial No. 636,413.

casing, on which the vulcanite or like cup is screwed, is formed with aseries of bosses at its rim, by buckling out or otherwise bossing thethin metal, and the screw thread by which the cap is secured is formedin the bosses. The screw is therefore an interruptedone and the threadis formed in thickened or strengthened parts of the metal so that thereis no need to provide a thickened rim for the case, which can thereforebe of thin metal throughout.

In order that the said invention may be clearly understood and readilycarried into effect, the same will now be described more fully withreference to the accompanying drawings, in which Figure 1 is a sideelevation of the receiver with the vulcanite cap removed,

Figure 2 is a face view showing the interior of the receiver,

Figure 3 is a cross section of the complete receiver,.

Figures 4 and 5 are, respectively, face and side views of a magnetstamping showing one form of the invention; and

Figures 6 to 9 show modified forms of sheet metal magnet stamping.

A is the receiver casing. B is the vulcanite or other cap perforated inthe usual manner and screwed upon the casing A. C is the diaphragmgripped at its edges between the casing and cap. D is the magnet whichis stamped from sheet metal with integral pole pieces (1 which areafterwards bent up on which the receiving coils E are mounted.

In the form of magnet shown in Figures 1, 2 and 3 an approximatelysemi-circular stamping is employed and the blank is stamped out of sheetmetal in the form shown in Figure 4, the integral pole piece tongues dbeing indicated in dotted lines before turning up to form the polepieces. It will be seen that these tongues when flat extend past eachother so as to lie side by side and therefore when they are turned up atright angles, as indicated in Figure 5, they are spaced sufficientlyapart to accommodate the receiver coils E but are separated by adistance which is considerably smaller than their combined lengths aridin fact is,as shown, smaller than the len th of either pole piece. Thislength of poIe piece is obtained by causing the tongues to extend pastor overlap each other so that when bent up they form pole pieces whichare staggered and are, therefore, not limited in length by the distanceseparating them. It is, of course,

cent and separated by a convenient distance, the spacing of the polepieces depending.

upon the shape and disposition of the tongues.

The ma net is secured in the casing by screw stu s F passing through thestud holes 0! in the part of the magnet stamping adjacent to the polepieces, these studs passing through insulating bushes-and form terminalsfor connecting up the receiving coils E through the tongues f. I

To permit of the casing A, usually ofaluminum or aluminum alloy, beingmade as light as possible without undulyreducing its strength at thescrew threaded portion, the casing is stamped up near its rim with anumber of shallow bosses a, forming slight recesses as seen from theinside and indiated in Figure 3, these bosses being'screw threaded sothat the threadwhen cut is entirely external to the main surface of thecasing and the casing is thus not weakened as is usually the case by ascrew thread out completely around its circumference and, therefore,effectively thinning the metal at the part receiving the perforated capB. The screw threaded bosses (1 preferably lie just within the edge ofthe casing so that the edge itself is of uninterrupted circular form.The bosses are shallow and are just sufiicient to receive the thread.Any convenient number of bosses may be employed, the receiver shown inthe drawings having four.

Figure 6 shows a slight modification of the magnet form in which thestamping D forms somewhat more than a semicircle and the tongues or polepieces at are directed inwardly, parallel to each other so that whenbent up they stand side by side with adjacent edges. The space betweenis made I sufficient to accommodate the coils.

In Figure 7 the stamping D is in the form of a cross and two pairs ofpole pieces d alternately N and S, are made by bending up the tongueswhich radiate from the centre to form the cross.

In Figures 8 and 9 astamping D is-made of star form, with four longerand four shorter radiating tongues (Z and d which 'when bent up 'forinan outer and an inner rin of pole pieces of opposite polarities asindicated. This allows a single magnet coil E to be employed between thetwo pole rings. Obviously the number of pole pieces may be'variedaccording to the size of the magnet.

What I claim and desire losecure by Let ters Patent of the UnitedStatesis 1. A magnet for telephone receivers comprising a sheet metal stampinghaving pole pieces integral therewith-and bent up substantially at rightangles to the plane of saidstamping, as set forth.

2.'A magnet for telephone receivers comprising a stamping havingintegral extension pieces thereon extending past each other which whenbent up substantially at right angles to the plane of said stamping formp0 e pieces, as set forth.

3. In atelephone receiver, the combination'including a magnet formedfrom sheet metal stamping, pole pieces integral with said magnet andbent up substantially at right angles to the plane of said magnet, andelectrical windings mounted on said pole pieces, as set forth.

4. A magnet for telephone receivers comprising a sheet metal stampingpartly circular 1n outline, two inwardly projecting tongues integraltherewith and parallel to one another which form pole pieces when bentup substantially at right angles to the plane of said stamping, as setforth.

5. A telephone receiver including in combination a magnet formed fromsheet metal stamping, pole pieces integral with said mag'rgtboand bentup substantially at right angle. the plane of said magnet, electricalwindings mounted on said pole pieces and a daiphragm adapted to bevibrated by said magnets, as set forth.

6. In a telephone receiver, a screwed outer cap and a case having anumber of shallow bosses in its rim, which bosses are screw threaded toreceive the said cap.

SIDNEY GEORGE BROWN.

